线性功能 [英] Linear function

问题描述

我需要编写一个分段函数，可以将百分比从95到65并将其转换为gpa值。技巧是，95 = 4.0,94 = 3.9,93 = 3.8,92 = 3.7，并且每个百分点继续减少.1，直到它达到65 = 1.0。如果不手动输入大量的其他内容，我就会变得难以理解。

  $（＃theButton ）.click（function（）{
 var perc = $（＃perc）。val（）; 
 var hardperc =（1 +（（perc-65）/ 10））; 
 perc = parseFloat（perc）; 
  

解决方案

如果你想要简单的线性归一化，那么下面的函数应该可以做到。不是使用重复的逻辑或条件，你可以使用一些数学。

  //可重用的线性规范化functionconst linearNormalize =（fromMin，fromMax，toMin，toMax）=> value => {//规范化输入值var pct =（value  - fromMin）/（fromMax  -  fromMin）; var normalized = pct *（toMax  -  toMin）+ toMin; // Cap输出到min / max if（normalized> toMax）回到Max; if（normalized< toMin）返回Min; return normalized;} //包装函数与您的特定inputsConst gradeToGpa = linearNormalize（65,95,1.0,4.0）; console.log（gradeToGpa（78））;  

使用 Scott Sauyet 咖喱功能建议：

< pre class =snippet-code-js lang-js prettyprint-override> const linearNormalize =（fromMin，fromMax，toMin，toMax）=> value => {var pct =（value - fromMin）/（fromMax - fromMin）; var normalized = pct *（toMax - toMin）+ toMin; if（normalized> toMax）返回到; if（normalized< toMin）返回Min; return normalized;} const gradeToGpa = linearNormalize（65,95,1.0,4.0）; console.log（gradeToGpa（78））;

I need to write a piecewise function that can take a percentage from 95 to 65 and convert that to a gpa value. The trick is, 95=4.0, 94=3.9, 93=3.8, 92=3.7, and that continues decreasing by .1 per percentage point until it hits 65=1.0. I'm becoming stumped how to code this without manually entering in a ton of else-ifs.

$("#theButton").click(function() {
    var perc = $("#perc").val();
    var hardperc = (1+((perc-65)/10));
    perc = parseFloat(perc);

解决方案

If you want simple linear normalization then the following function should do the trick. Rather than use repeated logic or conditionals, you can just use some math.

//Reusable Linear Normalization function
const linearNormalize = (fromMin, fromMax, toMin, toMax) => value => {
  //Normalize the input value
  var pct = (value - fromMin) / (fromMax - fromMin);
  var normalized = pct * (toMax - toMin) + toMin;

  //Cap output to min/max
  if (normalized > toMax) return toMax;
  if (normalized < toMin) return toMin;
  return normalized;
}

//Wrapper function with your specific inputs
const gradeToGpa = linearNormalize(65, 95, 1.0, 4.0);

console.log(gradeToGpa(78));

With Scott Sauyet's curried functions suggestion:

const linearNormalize = (fromMin, fromMax, toMin, toMax) => value => {
  var pct = (value - fromMin) / (fromMax - fromMin);
  var normalized = pct * (toMax - toMin) + toMin;

  if (normalized > toMax) return toMax;
  if (normalized < toMin) return toMin;
  return normalized;
}

const gradeToGpa = linearNormalize(65, 95, 1.0, 4.0);

console.log(gradeToGpa(78));

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